DNA microarray may help reveal reason behind coral reefs' deaths

Washington, Feb 5 (ANI): Scientists have developed a DNA microarray that may shed light on coral disease, which may help them learn how to preserve coral, one of the ocean's most important denizens.

The scientists, who developed the innovative DNA array, were from the Lawrence Berkeley National Laboratory and the University of California (UC).

The technique catalogs the microbes that live among coral in the tropical waters off the coast of Puerto Rico.

Through this method, scientists found that as coral becomes diseased, the microbial population it supports grows much more diverse.

It's unclear whether this surge in microbial diversity causes the disease, or is a result of it.

What is clear is that coral disease is accompanied by a microbial bloom, and the DNA array, called the PhyloChip, offers a powerful way to both track this change and shed light on the pathogens that plague one of the ocean's most important denizens.

"The PhyloChip can help us distinguish different coral diseases based on the microbial community present," said Shinichi Sunagawa, a graduate student in UC Merced's School of Natural Sciences who helped to conduct the research.

"This is important because we need to learn more about what's killing coral reefs, which support the most diverse ecosystem in the oceans. Losing them is much more than losing a reef, it means losing fish and marine mammals, even tourism," he added.

Worldwide, coral is threatened by rising sea temperatures associated with global warming, pollution from coastal soil runoff and sewage, and a number of diseases.

The organism's acute susceptibility to environmental change has given it a reputation as a canary in the coalmine: if it suffers, other species will soon follow.

Scientists have recently learned that healthy coral supports certain microbial populations, while coral inflicted with diseases such as White Plague Disease support different populations.

Understanding these microbial shifts could illuminate the magnitude and causes of coral disease, and possibly how to stop it, which is where the PhyloChip comes in.

The credit card-sized chip can quickly detect the presence of up to 9,000 species of microbes in specially prepared samples of air, water, soil, blood, and tissue.

The chip is carpeted with thousands of probes that scour a sample for the unique DNA signatures of most known species in the phyla bacteria and archaea. Specifically, the probes bind with a gene, called 16S rRNA, which is present in all life.

According to Todd DeSantis, on of the array's developers, "It's a fast and inexpensive way to conduct a complete microbial community assessment of healthy and diseased corals." (ANI)